Two people, Kawai Tomoki and Komori Yukino, were enjoying their unfamiliar drive date. They are a college couple who have just started dating. When their car broke down due to a flat tire, they left it behind and sought help, eventually arriving at the Black Rose Mansion. Thanks to the bewitching charm of Mamiya Marie, the two are allowed inside the mansion and are overwhelmed by its magnificent and luxurious space. In this mansion, there are four residents including the maid Aira, Marie's beautiful daughter Mamiya Maria, and another girl(?) named Takamizawa Rui who wears a boldly modified maid outfit with a collar, large cat ears, and even a tail-like attachment saying "My name is Takamizawa Rui-nyan!". Tomoki and Yukino, who will be spending a few days in the secluded Western-style mansion, the Black Rose Mansion, do not yet know that they will become prey to the bizarre feast that is about to begin.